Sunset Test

Here is a very easy test that demonstrates that the earth is a globe.

Find a spot where you have a view of the horizon. Now, lay down on the ground and watch the sun dip below the horizon. At the moment the sun completely disappears stand up. You will see a small sliver of the sun for a few seconds. Alternately, go up on the second floor, or higher, of a building, and you'll see even more of the sun. Another version of this test is to use a drone that, at say, a 100' elevation, would see even more of the sun while you on the ground you wouldn't see it at all.

This could only happen with a globe. But, the flat earth believers say the sun has gone past the point you can see it because of distance. If that were true, the elevation of the viewer wouldn't matter, and this simple experiment wouldn't work.